Generally, an instrument panel is mounted in front of a driver and front passenger in a vehicle. The instrument panel typically contains gauges, audio system, air-conditioner unit, glove box, ashtray, various switches and the like and separates the engine room and passenger compartment.
The middle lower portion of the instrument panel is formed with a center panel containing a heater control unit. The heater control unit adjusts, in particular, raises the temperature of the passenger compartment, determines which outlets discharge the heated air, and controls the speed of the fan.
The heater control unit is typically manipulated by buttons. The buttons may be in a rotary switching type (rotating knobs to regulate the temperature and direction of the heated air), push-button type, seesaw type or the like.
In order to locate the heater control buttons during night driving, the buttons are conventionally printed with color markings on the surface thereof and equipped with a back light therein. The back light is preferably a Light-Emitting Diode (LED).
However, there is a drawback in the conventional heater control buttons in that although the marking colors and LED colors should match each other, the lights emitted from the LED (back light) blend in the buttons due to a lack of separation therebetween, thus deteriorating the clearness of the marking colors and marketability of the heater control buttons.